Organic light emitting diodes (OLED) use the principles of electrophosphorescence to convert electrical energy in an OLED into light in a highly efficient manner. OLEDs are self-emitting apparatuses that do not require a backlight. Having the advantages of a wide viewing angle, high contrast, fast response, high flexibility, a wide working temperature, and a simpler structure and manufacturing process, they have found a wide range of applications in display field.
Organic material layers in an OLED substrate can be formed by depositing a liquid organic material onto the substrate by in-jet printing or coating. The printing method may be continuous or non-continuous. In a continuous printing process, the organic material can be applied using maskless, non-contact methods, and can be sequentially printed. Typically, the nozzle has a large opening which is not prone to clogging. The continuous printing is scalable and may be used for various ink compositions.